The present disclosure relates to semiconductor memories. More particularly, the present disclosure relates to storage devices in which a wear level thereof is managed, and to methods for managing the wear level of storage devices.
Nonvolatile memories retain stored data even in the absence of supplied power. Examples of nonvolatile memories include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable and programmable ROM (EEPROM), flash memory, phase-change RAM (PRAM), magnetic RAM (MRAM), resistive RAM (RRAM), ferroelectric RAM (FRAM), and the like.
With advancements in semiconductor manufacturing technologies, nonvolatile and other memories have experienced higher and higher degrees of device integration, resulting in ever higher memory capacities per unit area and per unit cost. However, the resultant scaling down of the memories can create unforeseen operational problems over time which can degrade reliability. These and other problems can be mitigated, and the lifespan of a nonvolatile memory extended, by adopting wear leveling techniques in which erasures and rewrites are distributed evenly across a cell array or arrays of the nonvolatile memory.